1. Field of the Invention
The present invention relates to a polysiloxane and a method of preparing the same, a silicon-containing alicyclic compound, and a radiation-sensitive resin composition containing the polysiloxane suitable for use in microfabrication utilizing radiation.
2. Description of the Background Art
A recent strong demand for high density and highly integrated LSIs accelerates miniaturization of wiring patterns.
Using short wave rays in a lithographic process is one method for miniaturizing wiring patterns. In recent years, deep ultraviolet rays typified by a KrF excimer laser (wavelength: 248 nm) or an ArF excimer laser (wavelength: 193 nm), electron beams, X rays, and the like are being used in place of ultraviolet rays such as g-line (wavelength: 436 nm), i-line (wavelength: 365 nm), etc. Use of an F2 excimer laser (wavelength: 157 nm) is also being studied.
Novolac resins, poly(vinylphenol), and the like have been used as resin components for conventional resist compositions. However, because these resins exhibit strong absorbance at a wavelength of 193 nm due to inclusion of aromatic rings in the structure, a lithographic process by an ArF excimer laser, for example, using these resins cannot provide high accuracy corresponding to high photosensitivity, high resolution, and a high aspect ratio.
Therefore, a resin for use in a resist, transparent to a wavelength of 193 nm or less, particularly to a wavelength of 157 nm, and exhibiting excellent dry etching resistance equivalent to or better than aromatic rings has been desired. A polysiloxane is one such a polymer. R. R. Kunz at al. of the MIT have reported their research results showing excellent transparency of a polysiloxane at a wavelength of 193 nm or less, particularly at 157 nm, commenting on superiority of this polymer as a resist in a lithographic process using radiation with a wavelength of 193 nm or less (J. Photopolym. Sci. Technol., Vol. 12, No.4, 1999). Moreover, polysiloxanes are known to exhibit excellent dry etching properties. In particular, a resist containing polyorganosilsesquioxane having a ladder structure is known to possess high plasma resistance.
Several resist materials using a siloxane polymer have also been reported. For example, Japanese Patent Publication No. 323611/1993 discloses a radiation-sensitive resin composition comprising a polysiloxane having an acid-dissociable group such as a carboxylic acid group, phenol ether group, etc., on the side chain, bonded to a silicon atom via one or more carbon atoms. Japanese Patent Application Laid-open No. 160623/1996 discloses a positive tone resist using poly(2-carboxyethylsiloxane) in which the carboxyl group is protected with an acid-dissociable group such as a t-butyl group. Japanese Patent Application Laid-open No. 60733/1999 discloses a resist resin composition in which a polyorganosilsesquioxane providing an acid-decomposable ester group is used. However, resist materials using these conventional siloxane polymers containing an acid-dissociable group have not been satisfactory in producing basic properties in a resist such as transparency to radiation, resolution, developability, and the like.
Japanese Patent Publication No. 302382/1999 discloses a siloxane polymer having a non-aromatic monocyclic or polycyclic hydrocarbon group or a bridged cyclic hydrocarbon group containing a carboxyl group on the side chain, at least part of the carboxyl group being replaced by a group unstable to an acid, and a resist material containing such a polymer. This resist material exhibits small absorbance of a KrF excimer laser (wavelength: 248 nm) or an ArF excimer laser (wavelength: 193 nm), produces fine pattern configuration, and excels in properties such as sensitivity, resolution, dry etching resistance, etc. However, even if the above-mentioned siloxane polymer is considered, there are few siloxane polymer useful as a resin component of a resist material. A new siloxane polymer which can provide a resist material effectively sensing radiation with a short wavelength, exhibiting high transparency to radiation and superior anti-dryetching properties, and excelling in basic resist properties, and a silicon compound which can produce such a siloxane polymer are important subjects of development in view of the fast advance in microprocessing technologies for semiconductors.
Therefore, an object of the present invention is to provide a novel polysiloxane useful as a resin component for a resist material effectively sensing radiation with a short wavelength, typified by a KrF excimer laser (wavelength: 248 nm), and an ArF excimer laser (wavelength: 193 nm), and an F2 excimer laser (wavelength: 157 nm), exhibiting high transparency to radiation and superior dry etching properties, and excelling in basic resist properties required for resist materials such as high sensitivity, resolution, developability, etc.; a method of preparing such a polysiloxane; a silicon-containing alicyclic compound providing this polysiloxane; and a radiation-sensitive resin composition comprising this polysiloxane.
Therefore, an object of the present invention is to provide a novel polysiloxane useful as a resin component for a resist material effectively sensing radiation with a short wavelength, typified by a KrF excimer laser (wavelength: 248 nm), and an ArF excimer laser (wavelength: 193 nm), and an F2 excimer laser (wavelength: 157 nm), exhibiting high transparency to radiation and superior dry etching properties, and excelling in basic resist properties required for resist materials such as high sensitivity, resolution, developability, etc.; a method of preparing such a polysiloxane; a silicon-containing alicyclic compound providing this polysiloxane; and a radiation-sensitive resin composition comprising this polysiloxane.